The present invention relates generally to electrical switches for use in motor vehicles and, more particularly, to a system and method for providing a vehicle switch module having a self-identifying switch function. The switch module enables the placement of switches in any of a number of locations consistent with a customer's desired switch customization requirement, while providing for the identification of a switch regardless of its location, such that switches can be placed in any position within a defined network on the vehicle without changing the switch's functionality or the system wiring.
Electrical switches are used in motor vehicles as control switches for switching the motor vehicle lighting, the windshield wipers, the rear windshield heating, the cruise control functions, the internal central locking and other functions on and off. A number of such switches can be combined as control panels in the dashboard, in the center console or the like. In specialty vehicle markets—such as heavy trucks, agricultural equipment, and construction equipment, for example—many original equipment manufacturers (OEMs) produce custom dashboards for their customers. In doing so, the OEMs allow the customers to pick options as well as their associated switch locations. While such customization is desirable from the standpoint of the customer, such customization leads to significant overhead expenses for the OEMs with respect to managing customer options for the dashboards. That is, present methods of managing production for customer dashboards having customized options and associated switch locations requires separate drawings and wire harnesses for every vehicle manufactured. Furthermore, some OEMs may even install the wires for every option sold, but only connect the wires used with the individual customer dashboard order.
In the mix of switch functions, some switches provide input signals to a vehicle's microprocessor-based controller, often referred to as a body controller, or electronic controller unit (ECU), which receives the signal and makes logic decisions regarding how that function is to be performed or activated. Other switches are wired directly to their intended loads. Those switches providing ECU input typically operate at very low current, typically in the range of 5 to 20 milliAmperes (mA), whereas direct-wired switches may handle loads up to 20 Amperes or more. Different contact materials are needed to accommodate these varying load ranges, as well as different sized wires and connectors. The arrangement or rearrangement of switches within the dashboard array is often limited in practice by the ability of the OEM to provide appropriate high current and low current wiring to support the desired functions. It is also common for OEMs to provide the same type of electrical connector and wires for all switch positions for economy and standardization, though the practice can result in a higher percentage of wiring errors at the time the vehicle is being assembled.
It would therefore be desirable to design a system and method that enables OEMs to reduce the cost of managing a custom dashboard. In doing so, the system and method would allow for one vehicle harness that could handle multiple customer options—thereby enabling vehicle OEMs to significantly reduce the engineering overhead and the wire count associated with a custom dashboard. It would also be desirable to provide a system where the user interface switch—particularly for direct-wired loads—may be located remotely from the direct-wired connection point, allowing for more standardized wiring layouts.